Technical noise in K‐band low‐noise cryogenic amplifier.

The performance of a 15–29 GHz low‐noise high‐electron‐mobility transistor amplifier at room and cryogenic temperatures is reported. The close‐to‐carrier technical noise is measured for frequency offsets from 100 mHz to 100 kHz and the effect of adjusting the DC power biasing is investigated. An order of magnitude improvement in intrinsic phase noise is achieved by optimising the bias settings away from manufacturer specifications, giving a single‐sideband phase noise power spectral density at 1 Hz offset of −100 dBc/Hz and −105 dBc/Hz for a 26.6 GHz carrier at room temperature and 6.5 K, respectively. [ABSTRACT FROM AUTHOR]